HALIFAX -- The murder trial of a former Halifax medical student resumes Monday, with his lawyer calling him a "model client" who has been unusually involved in his defence.

William Sandeson, 24, received special permission to use a computer while on remand at the Central Nova Scotia Correctional Facility in Halifax so he could review case material, said defence lawyer Eugene Tan.

"I think the unusual part is that he's reviewed every single piece of evidence that's been generated ... Every piece of paper, every report, every piece of video," Tan said outside court last week, adding that Sandeson took a paralegal course while in prison so he could better understand his case.

"I've never had a client who's been this involved, who knows the case this well, who understands the rules of evidence this well and who is fully participating in every decision that we make."

Sandeson was charged with first-degree murder on Aug. 20, 2015, four days after Taylor Samson -- a 22-year-old physics student -- was reported missing. His body has never been found.

Last week, as Sandeson's jury trial got underway, he sat at his lawyers' table with documents, a notepad and a laptop that he received permission to use during the proceedings.

In her opening address, Crown lawyer Susan MacKay said evidence will show police detected DNA matching Samson's genetic profile on a gun and a bullet found in Sandeson's Halifax apartment.

MacKay said the gun was found after police made an emergency entrance into the apartment "because they were concerned that Mr. Samson was being held hostage there" after officers read text messages between the two Dalhousie University students.

The last time Samson was seen alive, MacKay alleges, he was recorded on a surveillance video walking into Sandeson's apartment to sell 20 pounds of marijuana to the accused for $40,000.

"But for Taylor Samson, things didn't work out as planned," MacKay told the jury of seven women and seven men.

MacKay said surveillance video will show Sandeson leaving his apartment the morning of Aug. 17 carrying a small kitchen appliance box and a small duffel bag.

She said police were contacted by a lawyer on behalf of two men, one of whom was Sandeson's brother, and that police later recovered 20 pounds of marijuana from his brother's home inside what looked like the same appliance box and duffel bag.

"You will hear that they also found on this DNA with a profile that matches the profile of Taylor Samson," MacKay said.

MacKay added that the Crown will produce evidence that "will form the clear picture of William Sandeson's guilt beyond a reasonable doubt."

The jury has heard testimony from Samson's mother, Linda Boutilier, and four Halifax Regional Police officers.

Boutilier testified on Thursday that she was very close with her son. She said she gave two statements to police on Aug. 17 and that her other son later provided DNA samples.

Boutilier also revealed that her son had autoimmune liver disease that required daily medication. She told police her son would be OK without his medication for about a week, as long as he did not drink alcohol.

Later, Sgt. Tanya Chambers-Spriggs testified that she was at the police station on Aug. 17 when Boutilier arrived and told police about her son's disease, and that he may have had drugs on him at the time of his disappearance.

Sandeson, who is originally from Truro, N.S., is a former varsity track athlete who was set to start his medical studies within weeks of his arrest.